Investigation of the functions of glycoproteins at tumor cell surfaces will concentrate on epiglycanin, a glycoprotein implicated in masking histocompatability antigens in allotransplantable TA3 mouse mammary carcinoma ascites cells. The possible role of epiglycanin and epiglycanin-like glycoproteins in allotransplatability in the mouse and metastasis in experimental animals and humans will be pursued by means of a radioimmune assay involving the use of an antibody to epiglycanin, specific for the carbohydrate moiety, and 125I-labelled epiglycanin. A possible relationship will be investigated, in several hundred patients with metastatic cancer, between the concentration of epiglycanin-like glycoproteins present in the ascites fluids and sera and the type and severity of the malignancy. The antibody will be purified, Fab fragments isolated, and the location(s) of the combining site(s) on the epiglycanin molecule determined by electron microscopy of the Fab antibody-epiglycanin complex. n antibody to the protein moiety of epiglycanin will be made from th deglycosylated glycoprotein. This antibody will be used, in a radioimmune assay, to study early peptide precursors to epiglycanin. We will also study the role of lipid intermediates to epiglycanin synthesis and the relative rates of synthesis of O-linked and N-linked chains. Inhibitors to epiglycanin biosynthesis will be sought. The amonio acid sequence will be determined on deglycosylated epiglycanin. The types of N-linked chains, the sequences of carbohydrate residues in the N-linked chains, accomplished mainly by the use of specific glycosyl hydrolases, and the possible presence of fucose (H blood group activity) in these chains will be determined. Comparison will be made of the types and concentrations of neutral glycolipids in strain specific and strain nonspecific TA3 ascites tumor lines.